Pack of 3 coconut coir bricks. Each brick of our all-natural coco coir weighs approximately 500 grams and makes approximately 10 quarts after being hydrated. This is an eco-friendly product that consists of many coconut fibers compressed into a single brick. Hydrate with 1 gallon of water per brick and adjust the moisture content by adding 2 quarts of coarse vermiculite. Free of any additives or chemicals, this makes for an excellent bulk mushroom substrate.